This invention generally relates to a positionable element driving circuit for driving a positionable element to control the position of video heads, such as a bimorph type piezoelectric element.
Recently, an automatic tracking system has been introduced to a video tape recorder/reproducer. Such a system makes possible a proper tracking of the video track recorded on a video tape, reproducing no noise band pictures at any tape speed mode, for example, a normal speed mode, a slow motion mode, a still motion mode, a quick motion mode, a reverse motion mode and so on.
In the conventional automatic tracking system, the video heads are mounted on positionable elements such as a piezoelectric element. The piezoelectric element is supplied with displacing pattern signals which are equivalent to the video tracks on the video tape, and the video heads can trace the video tracks.
But a bimorph type piezoelectric element has nonlinear supplied voltage-position characteristics, and the tracking is difficult when the displacing pattern signals are changed.